I opened a duck egg this morning, it was laid on Saturday. There is a large green/black mark on the yolk. I have a drake so is this to do with it being fertile? Is is okay to eat? Just started out with the ducks in August so this is my first egg season- and also my first fertile season as the hens don't have a cockerel.

as i said in PM i rang my vet and asked him (as ive not come across this as yet as my ducks are still not giving up their lovely eggs, even though the drakes are very active indeed out there, my white ducks are all muddy and urrggh from them . They should lay anyday now)

any how he said it could be one of two things , 1 , your drake is doing his buisness well or it could be a meat spot , which is just bascially a tiny bit of tissue the yolk has collected along it travels down to become a egg, perfectly harmless and ok to eat yourself , but the public generally dont like seeing black spots on their eggs,thats if you sell them on ofcourse.

ive only kept ducks a short while myself so i thought i give my vet a ring as he pretty good . and im sure some one else who has kept ducks longer than me will be able to tell you .

I've had these marks on my call duck eggs in the past Jane. I wasn't too worried and continued to eat them/use them for baking. If the mark is quite large though, I would give that egg a miss but generally it's usually quite small.